# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
import os
import platform
import shutil
import subprocess
import tempfile
from pathlib import Path

from mozperftest.layers import Layer

# Add here any option that might point to a DMG file we want to extract. The key
# is name of the option and the value, the file in the DMG we want to use for
# the option.
POTENTIAL_DMGS = {
    "browsertime-binary": "Contents/MacOS/firefox",
    "xpcshell-xre-path": "Contents/MacOS",
}


class MacosDevice(Layer):
    """Runs on macOS to mount DMGs if we see one."""

    name = "macos"
    activated = platform.system() == "Darwin"

    def __init__(self, env, mach_cmd):
        super(MacosDevice, self).__init__(env, mach_cmd)
        self._tmp_dirs = []

    def _run_process(self, args):
        p = subprocess.Popen(
            args,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            universal_newlines=True,
        )

        stdout, stderr = p.communicate(timeout=45)
        if p.returncode != 0:
            raise subprocess.CalledProcessError(
                stdout=stdout, stderr=stderr, returncode=p.returncode
            )

        return stdout

    def extract_app(self, dmg, target):
        mount = Path(tempfile.mkdtemp())

        if not Path(dmg).exists():
            raise FileNotFoundError(dmg)

        # mounting the DMG with hdiutil
        cmd = f"hdiutil attach -nobrowse -mountpoint {str(mount)} {dmg}"
        try:
            self._run_process(cmd.split())
        except subprocess.CalledProcessError:
            self.error(f"Can't mount {dmg}")
            if mount.exists():
                shutil.rmtree(str(mount))
            raise

        # browse the mounted volume, to look for the app.
        found = False
        try:
            for f in os.listdir(str(mount)):
                if not f.endswith(".app"):
                    continue
                app = mount / f
                shutil.copytree(str(app), str(target))
                found = True
                break
        finally:
            try:
                self._run_process(f"hdiutil detach {str(mount)}".split())
            except subprocess.CalledProcessError as e:  # noqa
                self.warning("Detach failed {e.stdout}")
            finally:
                if mount.exists():
                    shutil.rmtree(str(mount))
        if not found:
            self.error(f"No app file found in {dmg}")
            raise IOError(dmg)

    def run(self, metadata):
        #  Each DMG is mounted, then we look for the .app
        #  directory in it, which is copied in a directory
        #  alongside the .dmg file.  That directory
        #  is removed during teardown.
        for option, path_in_dmg in POTENTIAL_DMGS.items():
            value = self.get_arg(option)

            if value is None or not value.endswith(".dmg"):
                continue

            self.info(f"Mounting {value}")
            dmg_file = Path(value)
            if not dmg_file.exists():
                raise FileNotFoundError(str(dmg_file))

            # let's unpack the DMG in place...
            target = dmg_file.parent / dmg_file.name.split(".")[0]
            self._tmp_dirs.append(target)
            self.extract_app(dmg_file, target)

            # ... find a specific file or directory if needed ...
            path = target / path_in_dmg
            if not path.exists():
                raise FileNotFoundError(str(path))

            # ... and swap the browsertime argument
            self.info(f"Using {path} for {option}")
            self.env.set_arg(option, str(path))
        return metadata

    def teardown(self):
        for dir in self._tmp_dirs:
            if dir.exists():
                shutil.rmtree(str(dir))